BACKGROUND Hemicraniectomy is an established neurosurgical procedure. However, before cranial vault reconstruction, it is imperative that sufficient scalp soft tissue is available for coverage of the reconstructed skull. OBJECTIVE To present 2 complex cases of posttraumatic patients requiring soft tissue expansion of the scalp before definite cranioplasty with use of a synthetic polyethylene graft. METHODS Two patients underwent decompressive hemicraniectomy for trauma and required delayed cranioplasty. Both patients had developed significant scalp contraction and presented with a paucity of soft tissue. These patients underwent a staged cranioplasty in which we first achieved scalp-tissue expansion adjacent to the craniectomy site over a prolonged interval. In a second stage, the patient underwent definite reconstructive surgery in which the subgaleal expanders were removed and polyethylene allograft cranioplasty was performed. RESULTS Cutaneous coverage of the underlying defect could be achieved in this setting without causing tension on the incision line secondary to the now available excess scalp tissue. CONCLUSIONS Repair of a cranial defect requires detailed attention to the available scalp and its size relationship to the skull defect to achieve a successful outcome with an aesthetically pleasing, reliable, and lasting result. Preoperative scalp tissue expansion is a valuable step in taking care of patients presenting with scalp soft tissue defect. This technique reduces the morbidity associated with conventional rotational and free-flap techniques.